Passwords and pin numbers are really important for your safety, especially when you are sharing devices. Make sure all your devices have random passwords with letters, numbers, and special characters. Sentences work well, too. The more difficult, the better. Use a different password for every device and for each platform/email address/website you use. That will make it easier for you to maintain your privacy, even if your computer is hacked or if your phone is stolen. Make sure you log out of accounts when you are done with your session. You can find various password manager apps online that make it easier for you to have and store complicated passwords.